In recent years, global warming due to an increase in concentration of carbon dioxide gas in the atmosphere is becoming a global issue. Active efforts have been made in various industrial fields aiming to develop techniques for reducing the release of carbon dioxide gas into the atmosphere. In the field of plastics production, plastic products have been conventionally produced from general-purpose oil-derived input materials, and after use, their waste is processed by incineration etc., resulting in discharge of carbon dioxide gas into the atmosphere. In recent years, however, attention is focused on plastics produced from plant-derived materials, which originate in carbon (carbon dioxide gas) in the atmosphere. In particular, research and development have been actively performed towards development of practical polylactic acid-based materials, which are generally high in transparency and relatively advantageous in terms of cost as well. On the other hand, polylactic acid has a disadvantage of being low in impact resistance, and its improvement has been called for. As a method to provide polylactic acid sheets with improved impact resistance, it is known that such improvement can be achieved by adding rubber particles to polylactic acid.
Japanese Unexamined Patent Publication (Kokai) No. 2006-232929 discloses a film formed of polylactic acid-based resin containing silicone/acrylic composite rubber. Furthermore, Japanese Unexamined Patent Publication (Kokai) No. 2009-173715, Japanese Unexamined Patent Publication (Kokai) No. 2007-119730 and International Publication WO 2007/063864 disclose a resin composition, sheet or film formed of polylactic acid containing core-shell type rubber as a multi-layered structure polymer.
However, sheets and films containing rubber such as disclosed in Japanese Unexamined Patent Publication (Kokai) No. 2006-232929, Japanese Unexamined Patent Publication (Kokai) No. 2009-173715, Japanese Unexamined Patent Publication (Kokai) No. 2007-119730 and International Publication WO 2007/063864 tend to be poor in slipperiness to cause problems during molding.
Thus, it could be helpful to provide polylactic acid-based resin sheets high in impact resistance, transparency, slipperiness, and creasability and particularly suitable for production of moldings.